Autoinjector received in external socket

ABSTRACT

The present invention relates to a device for automatic injection of a product, comprising:
         a body ( 3 ) housing a container, the container being movable relative to said body between an initial position, to an insertion position;   a safety shield ( 26 ) movable with respect to said container and said body between an insertion position to a protection position, when the user removes the device from an injection site;   an external socket ( 48 ) receiving the body and provided with selection means ( 53 ) which can be placed by a user:
           either in a first position, in which the body ( 3 ) and the external socket ( 48 ) are bound to each other, the safety shield extending beyond the distal end of both said body and said external socket in the protection position;   or in a second position, in which the external socket ( 48 ) is able to move axially in the distal direction with respect to the body ( 3 ), both the safety shield and the external socket extending beyond the distal end of said body, in the protection position.

The present invention relates to a device for automatic injection of aproduct in a very safe way, especially for self-injection.

In this application, the device has a longitudinal axis which is themain axis of the constitutive parts of said device. The distal end of acomponent or of a device is to be understood as meaning the end furthestfrom the user's hand and the proximal end is to be understood as meaningthe end closest to the user's hand. Likewise, in this application, the“distal direction” is to be understood as meaning the direction ofinjection, and the “proximal direction” is to be understood as meaningthe opposite direction to the direction of injection.

Some illnesses necessitate regular injections of drugs or products, forinstance on a daily basis. In order to simplify the treatment, someself-injectors have been provided in order to allow the patient toperform the injection on its own.

Of course, since the patient is usually neither a nurse nor an educatedperson in medical devices, such self-injectors must prove to be verysimple to use and also very safe. In particular, the insertion of theneedle must be performed at the right depth, the correct dose of productmust be injected, that is to say a complete injection must be performed,and the injector must be deactivated after use before it is disposed of.Preferably, the needle should not be exposed, before and after use, inorder to prevent any accidental needlestick injury.

In order to prevent needlestick injury after use of the injectiondevice, it has been proposed to provide the injection device with asleeve which is in a retracted position during the injection and whichextends over the needle when the user removes the device from theinjection site after completion of the injection. An alternativesolution is to have an injection device supported by a housing withinwhich the needle automatically retracts at the end of injection, withoutthe need for the user to remove the device from the injection site.

Nevertheless, depending on its apprehension of the injection operation,each patient may have different feelings about the step ofneutralization of the needle at the end of injection, and some mayprefer to have a sleeve that deploys over the needle when they removethe device from their skin while others may prefer that the needleautomatically retracts within the device so that they do not see theneedle.

In consequence, there is a need for self-injection devices that wouldallow the end user to choose whether he wishes that the needleautomatically retracts within the device at the end of injection withouthaving to remove the device from the injection site or on the contrarywhether he prefers to remove the device at the end of injection so as totrigger the extension of a sleeve for covering the needle.

The present invention meets this need by proposing a device forautomatic injection of a product into an injection site, said devicecomprising means allowing the end-user to choose how the neutralizationof the needle at the end of injection occurs.

The present invention relates to a device for automatic injection of aproduct into an injection site, said device having a longitudinal axisand comprising:

-   -   a body capable of housing a container, the container being        movable relative to said body between an initial position, in        which a tip of a needle provided on the container does not        extend beyond a distal end of said body, to an insertion        position, distally spaced relative to said initial position and        in which the tip of the needle extends beyond said distal end of        said body;    -   a safety shield arranged inside the body and receiving at least        partially the container, the safety shield being automatically        movable with respect to the container and said body between an        insertion position, in which the tip of the needle extends        beyond a distal end of said safety shield, to a protection        position, when the user has removed the device from the        injection site, in which the safety shield extends beyond the        distal end of said body over a length enough so that the tip of        the needle does not extend beyond a distal end of said safety        shield;

characterized in that said device further comprises:

-   -   an external socket receiving the body, having open proximal and        distal ends, said distal end of the external socket lying        substantially in the same plane as the distal end of the body,        in the insertion position;    -   a selection means provided on the external socket, and being        movable with respect to said external socket, where said        selection means can be placed by a user:        -   either in a first position, in which the body and the            external socket are bound to each other in the axial            direction, so that, in the protection position, the safety            shield extends beyond the distal end of both said body and            said external socket;        -   or in a second position, in which the external socket is            able to move axially in the distal direction with respect to            the body, the device being designed so that, in the            protection position, both the safety shield and the external            socket extend beyond the distal end of said body,            substantially over the same length.

The removal of the device from the injection site by a user causes theautomatic extension of the safety shield out of the distal end of thebody, in order to cover and protect the needle. This function is alreadyperformed in prior art devices.

Thanks to the arrangement according to the invention, when the selectionmeans are placed in the first position, the removal of the device fromthe injection site entails the axial movement of the safety shield inthe distal direction with respect to the body. Since the external socketand the body are mutually axially linked, the user sees the safetyshield extending beyond the distal end of the external socket or, inother words, the external socket moving up, together with the bodyplaced inside it, with respect to the safety shield. For the user, sucha functioning is similar to the functioning of some known devices,except that the body is located inside an additional external socket.

Moreover, when the selection means are placed in the second position,the removal of the device from the injection site still entails theaxial movement of the safety shield, with respect to the body, in thedistal direction. In other words, the body moves axially, in theproximal direction, with respect to the safety shield. However, sincethe external socket is no longer bound to the body in the axialdirection, this movement of the body does not cause a movement of theexternal socket, with respect to the safety shield. Consequently, themovement occurring within the device is a proximal displacement of thebody outside the safety shield and inside the external socket; saidsafety shield and said external socket do not move one with respect tothe other. The user sees no component extending beyond the distal end ofthe device, and can consider the needle has retracted inside the device.

Therefore, the invention makes it possible for the user to choosewhether he prefers the needle to be covered by a component (the safetyshield) extending around it, or to retract inside the device, once theinjection has been completed. This double function is achieved through aselection means which is very simple to manipulate. Furthermore, toachieve this goal, it is not necessary to provide two separate devices,depending on the user's choice. It is neither required to make use ofcomplicated means: an additional socket placed outside the body of anexisting device, provided with selection means, makes it possible toshift from one needle protection method to another.

In an embodiment, the selection means have a first part which extends atleast partially outside the socket so that it can be handled by a user,and a second part which extends at least partially inside the socket andwhich is designed to cooperate with a corresponding means provided onthe body, when the selection means are in the first position, in orderto bind the body and the external socket at least in one axialdirection.

For example, the free end of the second part of the selection means isdesigned to abut onto a shoulder provided on said body, in order toprevent an axial displacement of the socket with respect to the body inthe distal direction.

The selection means may comprise a lever housed in a window provided inthe external socket, the lever being able to swivel on a swiveling axiswith respect to the external socket. Preferably, the swiveling axis ofthe selection means lies in a plane substantially orthogonal to thelongitudinal axis and substantially tangential to the external socket.

In an embodiment, the external socket and the body have correspondingshoulders that mutually cooperate, at least in the insertion position,in order to prevent an axial displacement of the socket with respect tothe body in the proximal direction. With this arrangement, and when theselection means are placed in the first position with their second partabutting onto a shoulder provided on the body, the external socket andthe body can not move axially one with respect to the other, in eitherdirection.

The socket may further comprise a stop provided on its internal face,able to abut onto a shoulder arranged on said body, in the protectionposition and when the selection means are in the second position, inorder to prevent further axial displacement of the body in the proximaldirection with respect to the socket.

Preferably, the external socket has substantially the same length as thebody, the proximal and distal ends of the external socket lyingsubstantially in the same plane as the proximal and distal ends of thebody, respectively, in the insertion position.

In an embodiment, the movement of the safety shield between theinsertion and the protection position is automatically caused by elasticmeans which are arranged between the safety shield and the container andwhich expands when the user removes the device from the injection site.

The device of the invention will now be further described in referenceto the following description and attached drawings in which:

FIG. 1 is a partial exploded perspective view of an embodiment of thedevice of the invention;

FIG. 2 is a longitudinal cross section of the device of the invention,placed against a user's skin at an injection site, with the container inits insertion position before injection;

FIG. 3 is a longitudinal cross section of the device of FIG. 2, afterthe injection, with the selection means in the first position, in orderto cause the deployment of the sleeve;

FIG. 4 is a longitudinal cross section of the device of FIG. 2, afterthe injection, with the selection means in the second position, in orderto cause the retraction of the needle.

Referring now to the drawings, the present invention will now bedescribed in detail. FIG. 1 shows an exploded perspective view of a partof a device for automatic injection according to an embodiment of thepresent invention and generally designated by reference number 1.Actually, FIG. 1 shows an injection device 101 which is to form part ofthe device 1 for automatic injection of the invention of FIGS. 2-4. Thedevice 1 for automatic injection of the invention of FIGS. 2-4 comprisesthe injection device 101 as shown on FIG. 1 received within an externalsocket 48 (see FIGS. 2-3). The device 1 has a longitudinal axis 2 whichis the main axis of the constitutive parts of said device, as describedbelow. It is generally made of plastics.

The device 1 comprises a body 3 comprised of an upper body assembly 4and a lower body assembly 5 that may be connected to each other by meansof a snap-fit connection, screw-type connection, bayonet connection, orother means of connecting two parts together, in an unreleasable way ornot.

A container 6 such as, for example, a syringe, is received in the body3, the container 6 being movable axially relative to said body 3.Preferably, the container 6 is partially received in each of the upperand lower body assemblies 4, 5. The container 6 has a flange 7 definedat an open proximal end, and an injection needle 8 (see FIG. 2) at asubstantially closed distal end 9. Lateral walls 10 extend between theproximal and distal ends and define a reservoir 11 sized and shaped tocontain a predetermined amount of a product for injection. The injectionneedle 8 is in fluid communication with the reservoir 11 and provides anoutlet port of the container 6 for the product.

A needle shield 12 is provided at the distal end of the container 6 tocover and protect the needle 8 before use of the device 1. The needleshield 12, which is generally made of natural or synthetic rubbermaterial, also provides for a sealing means of the distal end of thecontainer 6 before use. A piston 34 (see FIG. 2) provided in thecontainer 6 is movable within the reservoir 11, with respect to thecontainer 6. The movement of the piston causes the product to beexpelled from said container 6 through the needle 8 during the injectionof the product into the patient.

The body 3 illustrated in FIG. 1 is only one possible embodiment of abody of a device according to the invention, and will be now brieflydescribed.

The upper body assembly 4 has a generally cylindrically shaped outersleeve 13 comprised of an inner cylinder 14 and an outer cylinder 15,the cylinders 14, 15 being linked to each other by at least a radialwall 35. The proximal end of the inner cylinder 14 is provided with twoflexible teeth 36, capable of being radially deflected, and with aninner radial rim 37. The outer cylinder 15 comprises an inner radial rim38 and, distally spaced from said inner radial rim 38, a shoulder 39forming a radial surface on the external face of said outer cylinder 15.

A push button 16, received in the outer sleeve 13, has a proximal endclosed by a transversal wall 17 which forms a pushing surface for theuser to exert a manual pressure on said push button 16, and a distalopen end 18. The distal face of the transversal wall 17 comprises twodistal teeth 40, and the distal open end 18 is provided with an outerradial rim 41 designed to cooperate with the inner radial rim 38 of theouter cylinder 15 of the upper body assembly 4 in the insertion position(see FIG. 2).

A plunger rod 19 for causing the piston to move with respect to thecontainer 6 is received within the inner cylinder 14 of said outersleeve 13 of the upper body assembly 4. The plunger rod is provided atits distal end with a flange 42 and at its proximal end with a radialstop 43.

A first spring 20 is provided between said plunger rod 19 and said innercylinder 14: the distal end of the spring 20 bears on the flange 42 ofthe plunger rod 19, and the proximal end of the spring 20 bears on thedistal face of the inner radial rim 37 of the inner cylinder 14. Spring20 causes displacement of the container 6 within the body 3 from aninitial position, in which a tip of the needle 8 does not extend beyondthe distal end of the body 3 to an injection position (FIG. 2), distallyspaced relative to said initial position and in which the tip of theneedle 8 extends beyond said distal end of said body 3 and is exposedover a predetermined length. Spring 20 further causes movement of thepiston within the container 6 to cause the product to be expelledtherefrom through the needle 8.

The lower body assembly 5 comprises a housing 21 which receives at leastpartially the container 6. The container 6 is movable relative to saidhousing 21 between an initial position, in which a tip of the needle 8does not extend beyond a distal end of the housing 21, and an insertionposition, distally spaced relative to said initial position and in whichthe tip of the needle 8 extends beyond the distal end of the housing 21and is exposed over a predetermined length (see FIG. 2).

The housing 21 has a general cylindrical shape and is open at both ends.The housing 21 has a distal part 22 and a proximal part 23 of greaterdiameter, joined by a radial wall 24. Two opposite windows 25 areprovided in the proximal part 23 of housing 21.

The lower body assembly 5 also includes a safety shield 26 that is atleast partially received within the housing 21. A proximal part of thesafety shield 26 is provided on its outer wall with two oppositeflexible tongues 27 capable of being radially deflected. The proximalpart of the safety shield 26 is also provided with two opposite firstproximal teeth 28 and with two opposite second proximal teeth 29,distally spaced from said first proximal teeth 28. The safety shield 26is provided, on its inner wall, with a radial rim 44, distally spacedfrom said flexible tongues 27.

The safety shield 26 is coupled to the housing 21 and is able to movebetween a first position and a second position in which the tip of theneedle does not extend beyond a distal end of the safety shield 26.

The device 1 further comprises an inner ring 30 which receives part ofthe proximal portion of said container 6, the inner diameter of saidinner ring 30 being less than the outer diameter of the flange 7 of saidcontainer 6 so as to prevent the container 6 from passing completelythrough the ring 30 when ring 30 and container 6 are assembled together.When assembled together, the inner ring 30 and container 6 may movetogether within the upper and lower body assemblies 4, 5 as thecontainer 6 is moved from its initial position to its insertionposition. The inner ring 30 comprises at least two distal legs 45 and atleast two outer radial rims 46, tangentially spaced from said two distallegs 45.

The device 1 also comprises an outer ring 31 which receives, at leastpartially, said inner ring 30. The outer ring 31 is provided on itsinner wall with at least two opposite radially flexible tongs 47 thatextend in the proximal direction.

A second spring 32 is provided between container 6 and inner ring 30. Asshown on FIG. 2, the distal end of the second spring 32 bears on theproximal face of the radial rim 44 of the safety shield 26, and theproximal end of said second spring 32 bears on a distal face of saidinner ring 30.

The device 1 of the present invention can also be provided with adeshielder 33 which carries the needle shield 12. Prior to use of thedevice 1, a user removes the deshielder 33, which also removes theneedle shield 12.

Finally, the device 1 comprises an external socket 48 which issubstantially cylindrical, with open proximal and distal ends 49, 50.The external socket 48 receives the body 3 and has substantially thesame length, the external socket 48 being arranged so that the bodycannot be seen by a user, at least in the initial and insertionpositions (see FIG. 2).

The external socket 48 has a shoulder 51 which is designed to cooperatewith the radial wall 24 of the housing 21, at least in the insertionposition (FIG. 2), in order to prevent an axial displacement of thesocket 48 with respect to the housing 21 in the proximal direction. Theexternal socket 48 also comprises a stop 52 on its internal face, closeto its proximal end 49, and a window, which is distally spaced from thestop 52.

In the window is housed a lever 53 which can swivel, with respect to theexternal socket 48, about an axis 54. The axis 54 lies in a planesubstantially orthogonal to the device axis 2 and substantiallytangential to the external socket 48, said swiveling axis 54 beingarranged substantially in the center of the lever 53. Said lever 53 actas a selection means, as will be explained later.

The lever 53 comprises a first part 55 which extends in the proximaldirection, at least partially outside the socket 48, and a second part56 which extends in the distal direction, at least partially inside thesocket 48, and which has a free end 57.

Initially, the lever 53 is placed in a first position (as in FIGS. 2 and3), where the first part 55 substantially entirely extends outside thesocket 48 and can be caught by a user. In this first position, the freeend 57 of the second part 56 is in abutment onto shoulder 39 of theouter cylinder 15 of the body 3, in order to prevent an axialdisplacement of the socket 48 with respect to the body 3 in the distaldirection. Because of the additional cooperation between the radial wall24 of the body and the shoulder 51 of the external socket 48, the body 3and the external socket 48 are bound to each other axially in bothdirections.

From the first position, and after the end of the injection, a user canpush the first part 55 of the lever 53, in order to place lever 53 inthe second position (FIG. 4), where the lever 53 is substantiallyparallel to the device axis 2. In this position, the lever 53 is nearlyentirely housed in the window: its first part 55 and second part 56 doesnot extend outside, respectively inside, the external socket 48.Consequently, the free end 57 of the second part 56 no longer cooperateswith shoulder 39 of the outer cylinder 15 of the body 3, and the body 3is thus free to move axially in the proximal direction with respect tothe external socket 48.

The general functioning of the device 1 will now be briefly explained.Some more details can be found in PCT/IB2007/002016.

The device 1 is provided to a user ready-to-use, the container 6 beingfilled with a predetermined dose of an injectable product.

Before use of the device 1, the container 6 is held in its initialposition in which the tip of the needle 8 does not extend beyond thedistal end of the body 3. The first spring 20 is held in a compressedcondition by flexible teeth 36 of the inner cylinder 14 being engaged inthe radial stop 43 of the plunger rod 19 and the flexible tongues 47 ofthe outer ring 31 being engaged in the radial rim 46 of the inner ring30. The inner ring 30 and thus the container 6 are thereby preventedfrom moving distally. The inner ring 30 is also prevented from movingproximally by the proximal part 23 of the housing 21.

Furthermore, the flexible tongues 27 of the safety shield 26 are engagedon an abutment surface of the housing 21, and the second spring 32 is innon-compressed or extended condition.

The flange 7 of the container 6 bears on the inner ring 30. Thecontainer 6 is therefore retained in its initial position by thecombined actions of the flexible teeth 36 of the inner cylinder 14, theradial stop 43 of the plunger rod 19 and the inner ring 30.

Prior to use, the user removes the deshielder 33 and the needle shield12 and places the device 1 against his/her skin at an injection site 58.Then, the container 6 is still retained in its initial position, and theneedle 8 is still protected by the safety shield 26.

The push button 16 is in a passive state such that depression by a useron the pushing surface 17 will not cause the device 1 to make aninjection. Indeed, the movement of the push button 16 in the distaldirection is possible but limited by retaining means (not described)which guarantee that the device 1 can not be triggered or activated atthis stage, for safety reasons.

The triggering of the device 1 of the invention requires at least twosteps.

In a first step, the user applies the device 1 on the injection site 58by means of the bearing surface 59 of the safety shield 26, whichinitially extends slightly further in the distal direction with respectto the distal end 60 of the housing 21. The safety shield 26 is thencaused to move relative to said housing 21 in the proximal direction,until the bearing surface 59 and the distal end 60 lie substantially inthe same plane (as in FIG. 2).

This movement makes it possible to deactivate the retaining means of thepush button 16, which is then in an active state. Furthermore, thecontainer 6 is also placed in an active state, since the movement of thesafety shield 26 has caused the flexible tongues 47 of the outer ring 31to deflect radially (thanks to the second proximal teeth 29 of thesafety shield 26), and thereby to disengage from the radial rim 46 ofthe inner ring 30. Although being in its active state, the container 6is retained in its initial position and can move to its injectionposition, in the distal direction, only if the push button 16 ispressed.

In a second step, the user can trigger the device 1 to start theautomatic injection, by pressing manually the push button 16, in thedistal direction. Consequently, the teeth 40 of the push button 16 comein contact with the flexible teeth 36 of the inner cylinder 14 and makethem deflect radially and outwardly. Since the flexible teeth 36 are nowdisengaged from the radial stop 43 of the plunger rod 19, the firstspring 20 is now free to expand, and it pushes distally the plunger rod19, the container 6 and the inner ring 30 to the injection position.Consequently, the needle 8 pierces the user's skin (position illustratedin FIG. 2) and the injectable product is then automatically expelledfrom the container 6 into the user's skin, by means of the expansion ofthe first spring 20.

During this insertion of the needle 8, the inner ring 30 has moveddistally and its distal legs 45 have come in contact with the flexibletongues 27 of the safety shield 26, causing them to be deflectedradially and inwardly. Moreover, the second spring 32 has been caused tocompress. Yet, the distal end of said second spring 32 bears on theradial rim 44 of said safety shield 26 which is maintained against theinjection site 58 by the distal pressure exerted by the user on thedevice 1 and said second spring 32 is therefore not free to expand.

Once the injection is complete, the user removes the device 1 from theinjection site 58. This automatically causes the safety shield 26 tomove distally with respect to the body 3 (being moved away from thecontainer 6 and body 3 thanks to the expansion of the second spring 32),i.e. to extend from the housing 21 and to cover and protect the needle8. In other words, the body 3 moves in the proximal direction withrespect to the safety shield 26. In this protection position, the safetyshield 26 may be locked against proximal movement, thereby preventingunintended access to the contaminated needle 8.

The removal of the device 1 from the injection site 58 causes otherrelative movements of the various components of the device 1, whichmovements depend on the position of the lever 53.

If the lever is in the first position (FIG. 3), as explained above, thebody 3 and the external socket 48 are axially bound to each other, inboth directions.

As a consequence, the external socket 48, as the body 3, moves in theproximal direction with respect to the safety shield 26. The proximaland distal ends 49, 50 of the external socket 48 remains substantiallyin the same plane as the proximal and distal ends of the body 3,respectively. Therefore, in the protection position, the safety shield26 extends beyond the distal end of both said body 3 and said externalsocket 48. For the user, the visual effect is similar to a conventionaldevice where the safety shield expands to cover the needle.

If the lever is in the second position (FIG. 4), as explained above, thebody 3 is free to move axially in the proximal direction with respect tothe external socket 48.

As a consequence, when the body 3 moves in the proximal direction withrespect to the safety shield 26, the external socket 48 is not caused tomove similarly. Therefore, in the protection position, the safety shield26 extends beyond the distal end of said body 3 but remainssubstantially in the same plane as the distal end of the external socket48. For the user, the visual effect is the following: the needle hasretracted in the proximal direction within the device. It should benoted that, in the protection position, the stop 52 provided on theexternal socket 48 is designed to abut onto the shoulder 39 of the outercylinder 15, in order to prevent the further axial displacement of thebody 3 in the proximal direction with respect to the socket 48.

The device of the invention makes it possible for the user to choosebetween two protection methods of the contaminated needle after theinjection step, in a very simple way since it is just necessary to pusha small lever.

Furthermore, this inventive device does not require a great modificationof existing devices provided with an expanding safety shield: theexisting device only has to be placed into an additional external socketprovided with the appropriate selection means.

Advantageously, and notably to avoid misuses (such as an accidentalactivation of the retraction, by placing the lever in the secondposition, before the end of injection), the lever can be judiciouslyplaced, enough protected from untimely handling, and clearly identified.

In case the user forgets to push the lever and then removes the devicefrom the injection site, the needle will all the same be protectedbecause of the automatic deployment of the safety shield. Consequently,the device of the invention remains as safe as known devices.

The invention claimed is:
 1. A device for automatic injection of aproduct into an injection site, said device having a longitudinal axisand comprising: a body capable of housing a container, the containerbeing movable relative to said body between an initial position, inwhich a tip of a needle provided on the container does not extend beyonda distal end of said body, to an insertion position, distally spacedrelative to said initial position and in which the tip of the needleextends beyond said distal end of said body; a safety shield arrangedinside the body and receiving at least partially the container, thesafety shield being automatically movable with respect to the containerand said body between an insertion position, in which the tip of theneedle extends beyond a distal end of said safety shield, to aprotection position, when the user has removed the device from theinjection site, in which the safety shield extends beyond the distal endof said body over a length enough so that the tip of the needle does notextend beyond a distal end of said safety shield; an external socketreceiving the body, having open proximal and distal ends, said distalend of the external socket lying substantially in the same plane as thedistal end of the body, in the insertion position, said external socketdefining an inwardly extending shoulder configured to interferinglyengage a portion of said body upon a predetermined extent of proximalmovement of said external socket relative to said body, said interferingengagement preventing further proximal movement of said external socketrelative to said body; a selection means provided on the externalsocket, and being movable with respect to said external socket, wheresaid selection means can be placed by a user: either in a firstposition, in which the body and the external socket are bound to eachother in the axial direction, so that, in the protection position, thesafety shield extends beyond the distal end of both said body and saidexternal socket; or in a second position, in which the body is able tomove axially in the proximal direction with respect to the safetyshield, the device being designed so that, in the protection position,both the safety shield and the external socket extend beyond the distalend of said body, substantially over the same length.
 2. Deviceaccording to claim 1, characterized in that the selection means have afirst part which extends at least partially outside the socket so thatit can be handled by a user, and a second part which extends at leastpartially inside the socket and which is designed to cooperate with acorresponding means provided on the body, when the selection means arein the first position, in order to bind the body and the external socketat least in one axial direction.
 3. Device according to claim 2,characterized in that the free end of the second part of the selectionmeans is designed to abut onto a shoulder provided on said body, inorder to prevent an axial displacement of the socket with respect to thebody in the distal direction.
 4. Device according to claim 1,characterized in that the selection means comprise a lever housed in awindow provided in the external socket being able to swivel on aswiveling axis with respect to the external socket.
 5. Device accordingto claim 4, characterized in that the swiveling axis of the selectionmeans lies in a plane substantially orthogonal to the longitudinal axisand substantially tangential to the external socket.
 6. Device accordingto claim 1, characterized in that the socket comprises a stop providedon its internal face, able to abut onto a shoulder arranged on saidbody, in the protection position and when the selection means are in thesecond position, in order to prevent further axial displacement of thebody in the proximal direction with respect to the socket.
 7. Deviceaccording to claim 1, characterized in that the external socket hassubstantially the same length as the body, the proximal and distal endsof the external socket lying substantially in the same plane as theproximal and distal ends of the body, respectively, in the insertionposition.
 8. Device according to claim 1, characterized in that themovement of the safety shield between the insertion and the protectionposition is automatically caused by elastic means which are arrangedbetween the safety shield and the container and which expands when theuser removes the device from the injection site.